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CHAPTER 12 Marine Life and the Marine Environment

CHAPTER 12 Marine Life and the Marine Environment. Overview. More than 250,000 identified marine species Most live in sunlit surface seawater Species success depends on ability to Find food Avoid predation Reproduce Cope with physical barriers to movement.

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CHAPTER 12 Marine Life and the Marine Environment

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  1. CHAPTER 12 Marine Life and the Marine Environment

  2. Overview • More than 250,000 identified marine species • Most live in sunlit surface seawater • Species success depends on ability to • Find food • Avoid predation • Reproduce • Cope with physical barriers to movement

  3. Classification of living organisms • Three domains of Life • Archaea • Prokaryotic, includes “extremophile” bacteria • Bacteria • Prokaryotic, includes what used to be in Kingdom Monera • Eukarya • Eukaryotic cells • Includes Protists, Fungi, Plants, and Animals

  4. Archaea • Bacteria - Prokaryotic cells • Cell wall differs from those bacteria in Domain Bacteria • Includes extremophile bacteria • Acidophiles • Halophiles • Thermophiles • Etc. • These bacteria are found to chemosynthesize in hydrothermal vents

  5. Bacteria • Bacteria – prokaryotic cells • Cell wall made of peptidoglycan • Includes Staphylococcus, Bacillus, Vibrio, Pseudomonas, etc. • Only a very small % of bacteria are pathogenic • Bacteria are very important in things like nitrogen cycle, decomposition, food making, etc. • Cyanobacteria are photosynthetic bacteria

  6. Archaea and Bacteria • Most numerous organisms on Earth • Think about how much bacteria lives just on you • Viruses are thought to out number bacteria but if you are just talking about “live” organisms then bacteria are the most numerous • Simplest of organisms • But, can live in every thinkable habitat, even those once thought to be unsuitable to life, very successful

  7. Now we will talk about Domain Eukarya • Includes protists, fungi, plants, animals

  8. Eukarya - Protists • Algae • Photosynthetic • Can be unicellular, colonial, or multicellular • Multicellular - “seaweed” – kelp, sargassum, sea lettuce • Unicellular – phytoplankton, produce majority of oxygen in atmosphere, can cause red tides • Protozoans • Heterotrophic • Unicellular • Amoeba, paramecium

  9. Eukarya - Fungi • Heterotrophic • Secrete enzymes and absorb nutrition • Since they are heterotrophic, they are more closely related to animals than to plants • Multicellular (mold) or unicellular (yeast)

  10. Eukarya - Plants • Autotrophic, multicellular • Many plant species cannot tolerate saltwater • Very few species grow in/near ocean • Sea grasses • Mangroves • Dune plants

  11. Eukarya - Animals • Heterotrophic, multicellular, have motility at some point in life cycle • Wide variety • From simplest of animals (sponges) to most complex (mammals)

  12. Viruses • Acellular entities • Are they “alive”??? • Do not have the machinery for life processes, have to take over host cell • The ultimate “parasites”

  13. Taxonomic classification • Systemized classification of organisms • Kingdom • Phylum • Class • Order • Family • Genus • Species • Fundamental unit • Population of genetically similar, interbreeding individuals

  14. With new molecular methods (comparing DNA sequence and amino acid sequences of certain proteins), traditional taxonomy is changing • Taxonomists are discovering new relationships between species • Molecular data gives a clearer picture of relatedness as opposed to the traditional ways of classifying organisms: • Morphology, embryology, behavior, habitat, etc.

  15. Classification by habitat and mobility • Plankton (floaters) • Nekton (swimmers) • Benthos (bottom dwellers)

  16. http://i.ehow.com/images/GlobalPhoto/Articles/2110315/icephytoplankton-main_Full.jpghttp://i.ehow.com/images/GlobalPhoto/Articles/2110315/icephytoplankton-main_Full.jpg Plankton • Most biomass on Earth consists of plankton • Phytoplankton • Microscopic algae, Autotrophic • Zooplankton • Heterotrophic • Protozoans, tiny animals, larvae of larger animals • Bacterioplankton • Virioplankton • Viruses that infect bacteria and eukaryotic cells

  17. Plankton • Holoplankton • Entire lives as plankton • Example is algae, protozoans, small microscopic animals • Meroplankton • Part of lives as plankton • Juvenile or larval stages in the plankton • Examples are lobsters, some fish species, etc. • Macroplankton • Large floaters such as jellyfish or Sargassum • Picoplankton • Very small floaters such as bacterioplankton

  18. Nekton • Independent swimmers • Most adult fish and squid • Marine reptiles • Marine mammals

  19. Benthos • Epifauna live on surface of sea floor • Infauna live buried in sediments • Nektobenthos swim or crawl through water above seafloor • Most abundant in shallower water

  20. Hydrothermal vent biocommunities • Abundant and large deep-ocean benthos • Discovered in 1977 • Associated with hot vents • Bacteria-like archaeon produce food using heat and chemicals • “chemosynthesis instead of photosynthesis” http://bioinfo.bact.wisc.edu/themicrobialworld/Hydrothermal_vent.jpg

  21. Number of marine species • More land species than marine species • Ocean relatively uniform conditions • Therefore, less adaptation required, less speciation • Don’t get this fact confused with # of individual organisms • There are fewer different species in the ocean but greater # of individuals • Majority of life on Earth lives in the ocean!! • Diversity in the ocean is high, also – think about different types of fish (seahorses to sharks, for example) • Marine species overwhelmingly benthic rather than pelagic • Most of these will be in shallow coastal benthic areas where there is light and a lot of primary productivity

  22. Adaptations of marine organisms • Physical support • Buoyancy • How to resist sinking • Different support structures in cold (fewer) rather than warm (more appendages) seawater • Smaller size http://www.solaster-mb.org/mb/images

  23. Adaptations to marine life • Appendages to increase surface area • Oil in micro-organisms to increase buoyancy • Over-time, if these organisms die and sink to bottom • Can become offshore oil deposits Fish egg with oil droplet Fig. 12.9 http://www.rpgroup.caltech.edu/~natsirt/aph162/webpages/dylanandco/lab1/image

  24. Adaptations to marine life • Streamlining important for larger organisms • Less resistance to fluid flow • Flattened body • Tapering back end – fusiform http://www.wissenschaft-online.de/sixcms/media.php/591

  25. Adaptations to marine life • Narrow range temperature in oceans • Smaller variations (daily, seasonally, annually) • Remember it takes longer to change water temp than air temp • Deep ocean nearly isothermal

  26. Adaptations to marine life • Cold- versus warm-water species • Smaller in cooler seawater • More appendages in warmer seawater • Tropical organisms grow faster, live shorter, reproduce more often • More species in warmer seawater • More biomass in cooler seawater (upwelling) • Polar waters are much more productive (more plankton growth) than tropical waters

  27. Adaptations to marine life • Stenothermal • Organisms withstand small variation in temperature • Typically live in open ocean • Eurythermal • Organisms withstand large variation in temperature • Typically live in coastal waters

  28. Adaptations to marine life • Stenohaline • Organisms withstand only small variation in salinity • Typically live in open ocean • Euryhaline • Organisms withstand large variation in salinity • Typically live in coastal waters, e.g., estuaries

  29. Adaptations to marine life • Extracting minerals from seawater • High concentration to low concentration • Diffusion • Cell membrane permeable to nutrients, for example • Waste passes from cell to ocean

  30. Adaptations to marine life • Osmotic pressure • Less concentrated to more concentrated solutions • Isotonic • Hypertonic • Hypotonic

  31. Adaptations to marine life • Dissolved gases • Animals extract dissolved oxygen (O2) from seawater through gills Fig. 12.15

  32. Adaptations to marine life • Water’s transparency • Many marine organisms see well • Some marine organisms are nearly transparent to avoid predation

  33. Adaptations to marine life • Camouflage through color patterns • Countershading • Disruptive coloring • http://www.youtube.com/watch?v=PmDTtkZlMwM http://theplasticocean.blogspot.com/2012_07_01_archive.html

  34. Adaptations to marine life • Water pressure • Increases about 1 atmosphere (1 kg/cm2) with every 10 m (33 ft) deeper • Many marine organisms do not have inner air pockets • Collapsible rib cage (e.g., sperm whale)

  35. Main divisions of the marine environment • Pelagic (open sea) • Neritic (< 200 m) and oceanic • Benthic (sea floor) • Subneritic and suboceanic • Another classification scheme: • Euphotic • Disphotic • Aphotic

  36. Pelagic environments – Open ocean • Epipelagic • Mesopelagic • Bathypelagic • Abyssopelagic Fig. 12.19

  37. Benthic environments – ocean floor • Supralittoral • Transition from land to seafloor • Subneritic(under neritic) • Littoral (intertidal zone) • Sublittoral(shallow tidal zone to 200m) • Suboceanic • Bathyal(200-4,000m) • Abyssal (4000-6000m) • Hadal(below 6000m) Fig. 12.19

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